#include <stdio.h>

int main()
{
	int sign=1;
	double deno = 2.0,sum=1.0,term;
	while (deno <= 100)
	{
		sign = -sign;
		term = sign/deno;
		sum=sum+term;
		deno=deno+1;
	}
	printf("%f\n",sum);
}